This invention relates to an explosive emulsion composition. In a particular aspect, this invention relates to an explosive emulsion composition containing a nitroalkane.
Water-in-oil type of emulsions are very useful blasting agents in the explosives art because such emulsions have considerable water resistance. They can, therefore, be used in wet holes where oil-in-water or ANFO type blasting agents would be unsuitable. Also, they offer the advantages of safety and low material cost when compared to conventional high explosives, especially those containing metal particulates as sensitizers.
Although nitromethane is well-known in the explosives art, higher nitroalkanes, especially the nitropropanes, have received considerably less attention. However, it is known from Egly et al, U.S. Pat. No. 3,161,551 to provide water-in-oil emulsions utilizing nitroalkanes. These emulsions were said to be suitable for use in the preparation of blasting agents. Suitable emulsifiers included oxazolines, fatty acid salts of alkaline earth metals, polyoxyethylene derivatives of sorbitol esters and of fatty acids. The emulsions contained 50-70% ammonium nitrate, 15-35% water and 5-20% of an organic liquid including fuel oils and nitroalkanes. The emulsions were then mixed with additional ammonium nitrate to produce the blasting agent. However, according to R. B. Clay, U.S. Pat. No. 4,111,727, compositions of this type were found not to be reliably detonable without being gassed or aerated. Minnick, in U.S. Pat. No. 3,338,165, taught the preparation of gels using, among other ingredients, nitromethane and air-entrapping materials and in U.S. Pat. No. 3,419,444 taught the preparation of aqueous slurries in which gelled nitroalkanes were dispersed. Other workers have disclosed water-in-oil type emulsions useful as explosives, but none of them taught nitropropane-containing emulsions.
There is, therefore, a need for water-in-oil type of blasting agents wherein the nitropropanes can be used as a portion of the fuel.